the rabid animal's teeth-is as well established as any fact in medicine or in history. But fortunately the disease is rare and comparatively few physicians have been called upon to treat a case of it. It is reported that ninety-one persons have died of hydrophobia in the city of Chicago during the past ten years. The disease was known to the ancients and is very clearly described by Celus (B. C. 21). As long ago as 1813 the French physicians Magendie and Bouchet produced rabies in dogs by inoculating them with saliva obtained from a man suffering from hydrophobia. But our exact knowledge of the disease dates from the researches of the famous French chemist, Pasteur (1881 to 1886). Pasteur first announced his success in reproducing rabies in susceptible animals by inoculations with material from the nervous system-brain, spinal cord-in a communication made to the French Academy of Sciences on May 30, 1881. At the same time he reported his success in the discovery of "a method for considerably shortening the period of incubation in rabies. and also of reproducing the disease with certainty." This was by inoculations, made after trephining, upon the surface of the brain, with material obtained from the brain of a rabid animal. Dogs inoculated in this way developed rabies in the course of two weeks and died before the end of the third week. In a second communication (December 11, 1882) Pasteur reported his success in communicating the disease by intravenous injections of virus obtained from the central nervous system of rabid animals; also the experimental demonstration of the fact that all forms of rabies may be produced by the same virus; also, that all parts of the spinal cord of rabid animals are virulent, as well as all parts of the brain; also that an animal (dog) which had recovered from a mild attack after inoculation proved to be subsequently immune, and that "this observation constitutes a first step toward a discovery of the prophylaxis of rabies." In a subsequent communication (May 19, 1884) Pasteur presented evidence which demonstrated the fact that by successive inoculations in monkeys the period of incubation is prolonged and the virus of the disease attenuated; that this attenuated (milder) virus from the monkey when inoculated into a dog no longer produces fatal rabies; and that dogs so treated are subsequently immune. Having demonstrated these important facts Pasteur determined to make a test experiment which should convince the scientific world of the truth and value of his discoveries. At his request a commission was appointed by the Minister of Public Instruction to determine the efficacy of his method as applied to the protection of dogs. In his address before the International Medical Congress at Copenhagen (August 11, 1884) Pasteur gives the following account of the results of this test experiment. He says that he gave to the commission nineteen dogs which had been rendered immune against rabies by preventive inoculations. These nineteen dogs and nineteen control animals, obtained from the public pound, without any selection, were tested at the same time. The test was made upon some of the animals of both series by inoculations with virulent material from rabid animals, made upon the surface of the brain, by trephining; and upon others by allowing them to be bitten by rabid dogs; and upon still others by intravenous inoculations. Not one of the protected animals developed rabies; on the other hand, three of the control animals out of six bitten by mad dogs developed the disease; five out of seven which received intravenous inoculations died of rabies; and five which were trephined and inoculated upon the surface of the brain died of the same disease. In a subsequent report the commission, of which M. Bouley was president, stated that twenty-three dogs, which had been protected, were bitten by mad dogs and that all remained in perfect health, while sixty-six per cent. of the control animals, bitten in the same way, developed rabies within two months. Evidently this method could be applied upon a large scale for the prevention of rabies among dogs, and if these animals were thus protected, rabies would soon become practically extinct. The method is even more reliable than vaccination as a protection against smallpox. But its practical application on a large scale would be attended with great difficulties and would, no doubt, be opposed by a large proportion of the owners of dogs. There has, therefore, so far as I am informed, never been any attempt to apply this discovery of Pasteur's in a practical way for the prevention of rabies. But these preliminary experiments led to the discovery that animals and man may be rendered immune to the disease by protective inoculations made after they have been bitten by a rabid animal. I shall not attempt to give an account of the experiments which led Pasteur to this important discovery or of the methods employed for obtaining an attenuated virus, but will content myself with a summary statement of the results which have been attained in the practical application of this method of prevention. It is probably generally known that "Pasteur Institutes" for the treatment of persons bitten by rabid animals have now been established in all parts of the civilised world. During the year 1891, 1564 persons were inoculated at the Pasteur Institute in Paris with a total mortality of 0.57 per cent. In 324 of these cases the animal which inflicted the bite was proved to be rabid by experimental inoculations made in other animals-with an emulsion of the brain or spinal cord. This is now generally recognised as a conclusive demonstration that an animal, or man, from whom such virulent material has been obtained, was a victim of rabies. Perdrix (1890) in an analysis of the results obtained at the Pasteur Institute in Paris calls attention to the fact that the mortality among those treated has diminished each year and ascribes this to improvements in the method employed. In the cases with severe wounds upon the head and face larger doses of the virulent material are used at more frequent intervals. Perdrix gives the following statistics with reference to the location of the bite as influencing the results of treatment. Bitten upon the head, 684; died, 12 = 1.75% Recently the statistics of the Pasteur Institute in Paris for a period of sixteen years (1886 to 1901) have been published. During this period 112 deaths occurred among 25,986 persons inoculated-a mortality of 0.43 %. It is not claimed that all of the inoculated had been bitten by rabid animals. many cases it is impossible to ascertain whether the In |